Strongly-coupled Josephson junction array for simulation of frustrated one-dimensional spin models

TL;DR

This paper demonstrates how a capacitance-coupled Josephson junction array can simulate strongly frustrated one-dimensional Ising spin models without relying on small-coupling approximations, enabling more accurate quantum simulations.

Contribution

It develops a method to derive the Hamiltonian of large-scale Josephson junction arrays beyond the small-coupling limit and applies dynamical decoupling to engineer the desired spin model.

Findings

The Hamiltonian can be obtained without small-coupling approximation for large systems.

Dynamical decoupling effectively eliminates undesired couplings.

Numerical simulations confirm the system exhibits key features of frustrated spin models.

Abstract

We study the capacitance-coupled Josephson junction array beyond the small-coupling limit. We find that, when the scale of the system is large, its Hamiltonian can be obtained without the small-coupling approximation and the system can be used to simulate strongly frustrated one-dimensional Ising spin problems. To engineer the system Hamiltonian for an ideal theoretical model, we apply a dynamical decoupling technique to eliminate undesirable couplings in the system. Using a 6-site junction array as an example, we numerically evaluate the system to show that it exhibits important characteristics of the frustrated spin model.